A Hospital based study of High Resolution Computed Tomography and Conventional Radiography for Evaluation of Pathologies of Temporal Bone

Abstract

Background: Many imaging modalities have been in use for the evaluation of temporal bone lesions. Plain X-rays are cost-effective however; they provide limited details and hence sometimes may result in an inaccurate diagnosis. With the advent of HRCT, the method of imaging of temporal bone has evolved with special algorithms and multiplanar formats. In the present study, we tried to evaluate the different pathologies of the temporal bone with X-ray and HRCT. Methods: The study was conducted in the Departments of Otorhinolaryngology and Radiology, Prathima Institute of Medical Sciences, Naganoor, Karimnagar. A total of n=40 patients were identified and selected based on their symptoms and clinical findings suggestive of a lesion involving the temporal bone such as Otalgia, Otorrhoea, And Sensorineuronal deafness, pulsatile tinnitus, vertigo, and giddiness. These patients were subjected to high resolution computed tomography of the temporal bone on the 128 Slice CT Scanner (PHILIPS INGENUITY). The patients also underwent plain Radiography of temporal bone (CARESTREAM DRX-1 System). Results: Of the total n=40 patients studied the most common temporal bone disease was due to inflammation 85% and tumors were found in 15% of the patients. The common site of involvement of middle ear and mastoid air cells in chronic otitis media was epitympanum in n=30(90%) of cases, Mesotympanum in n=20(60%) of cases. In diseased ears, radiographs of the mastoids revealed pneumatised mastoid in 6(15%), diploic in 6(15%), and sclerosed mastoid in 28(70%) cases. HRCT temporal bone revealed pneumatised mastoid in 9(22.5%), diploic in 5(12.5%) and sclerosed mastoid in 26(65%) cases. Conclusion: The role of plain radiography is found to be limited to know the type of mastoid pneumatisation. It can also as Original Article detect bony erosion in few cases. Because of the ability to see temporal bone structures with great clarity, HRCT can be recommended not only in cases suspected with potential complications but also in all cases of temporal bone pathologies to know the extent of disease, inter-relationships of the tympanomastoid compartment with adjacent neurovascular structures, varied pneumatisation and the presence of anatomical variations, which should alert the clinician and guide in surgical approach and treatment plan.